DESIGN AND CONSTRUCTION OF UNTERRUPTIBLE POWER SUPPLY
ABSTRACT
Uninterruptible power supplies (UPS) are used to provide power when regular utility power is unavailable. Although they are commonly used for providing power in remote locations or emergencies, this is not because they are the same as auxiliary power units, emergency power units or standby generators. Unlike the aforementioned power sources, UPS provides an immediate and continuous supply of power to a device, hence protecting it from power interruption and allowing time for auxiliary or emergency powers, to kick in equipment to be safely shut down or utility power restored. The major aim of this was to design a system which will be able to convert battery voltage(12v) to 220v, which is equivalent to wall outlet and secondly able to charge the battery. The chapter one of this work, gives the over-view of UPS, it’s importance, uses, and application and some of its special features like its ability to correct frequency instability and many more. Secondly, this work dealt with all components used in the construction of the device, there working condition and uses. Some basic abstract phenomenon were also treated like wave forms and electronic switching. The chapter three, basically dealt on all electrical measuring instrument used in and on the device, how they are used, why and where. The fourth chapter explains how the components where assembled into section and the sectional connection used to form the device. The last chapter is a simple conclusion with honest recommendation.
CHAPTER ONE
INTRODUCTION
As blackouts roll through power-starved communities, the threat to you and your computer is not the lack of electricity, but the change in power. When the lights are off and you are about to start any industrial or computer-based projects, all your efforts will be wasted. Even when your system acts as a server, a sudden shutdown could disrupt the processing of many others. You can make your work immune to the intransigence of rolling blackouts and protect against many other types of unexpected power disturbances. Your secret weapon is the uninterruptible power supply or uninterruptible power source. Commonly called the UPS, this devices is a cleaver threefold package-a set of battery, an inverter that transforms the low-voltage direct current of the batteries into the standard alternating current equivalent to your wall outlet, and a battery changer that assures that reserve power storage system (the batteries) with interfaces to mach it to utility power and your computer system. A UPS differs from an auxiliary emergency power system or standby generator in that it will provide instantaneous or near-instantaneous protection from input power interruptions by means of one or more attached batteries and associated electronic circuitry for low power users, and or by means of diesel generators and flywheels for high power users. While not limited to protecting any particular type of equipment, a UPS is typically used to protect computers, data centers, telecommunication equipment or other electrical equipment where an unexpected power disruption could cause injuries, fatalities, serious business disruption and/or data loss. UPS units range in size from units designed to protect a single computer without a video monitor (around 200 VA rating) to large units powering entire data centers, buildings, or even cities. The UPS is designed to project against changes, specifically a temporary loss of electrical supply.
This project focuses on conversion of AC to DC and from DC to AC power inverters, which aim to efficiently transform a DC power source to a high voltage AC source, similar to power that would be available at an electrical wall outlet. Inverters are used for many applications, as in situations where low voltage DC sources such as batteries, solar panels or fuel cell must be converting electrical power from a car battery to run a laptop, TV or cell phone.